Improve chat tool rendering and history details

[aniket-s-kulkarni]

Summary

• fix chat model rendering so structured final answers and approval events render correctly in one-shot and interactive chat
• add optional tool detail output with timestamps, durations, and detailed tool results for and
• add coverage for renderer output, approval payload handling, and transcript history rendering

Testing

• uv run pytest tests/test_commands/test_chat.py tests/test_chat_render.py
• uv run dremio chat -m 'who reports to Myra Richmond'
• uv run dremio chat history 286fd980-fcc4-45de-a3af-f3a62153bc97 --show-tool-details